Aggregats of alpha-Cristobalite in the LDG If the very hot Si O2-melt cools down, amorphous lechatelierite (Silica) be produced at 1500-1000C.
During further cooling existing beta-cristobalite be converted to alpha-cristobalite at about 272C.
Tiny, irregularly formed bubbles, and light- and dark-brown bands can enforce the homogeneous glassy mass.
The viscosity is essentially greater than at tektites.
The melting point is with 1727-1713 C more as 500 higher, than which other natural glasses.
Beside the bubbles different kinds of further inclusions are to be recognized. 1996; KOEBERL 1997 have found that the contents of siderophile elements, such as Co, Ni and Ir, are significantly enriched in some rare, dark bands that occur in some LDG samples.
To this (e.g.) belong smallest crystal-grains of Quartz similar minerals alpha-Tridymite and alpha-Cristobalite. KOEBERL (1997) studied such dark bands and found that the contents of Fe, Mg, and Ni are high in the dark zones and low in the "normal" LDG.
The Desert Glass differs from the Tektites also by higher capacity of water inclusions (0.050 - 0.200 wt.%).
The colours of the LDG's varies from light-yellow, honey-yellow, green-yellow, milky-white to black-grey.
FELLER supposes, that faults have emerged in the area, which were expanded up to 4000 m under the earth's surface.
On fissures sour magma penetrated at the earth's surface.
Measurements based on the fission-track method determined an age of 29 - 28 Ma (Oligocene). The process can be described as an orthomagmatic hydrotherme.